The present invention relates to a method of controlling advanced water distribution networks for pressure zones, pressure modulation and such. More particularly the invention relates to the use of acoustic wave propagation through the medium itself to eliminate the additional costs of communication between sensors and controllers.
Control of processes is a broad general concern for every industry, particularly where fluids such as water are distributed in a network of pipes, vessels, containers and tanks. Often it is necessary to know conditions at various remote locations in a process in order to control the overall operation effectiveness and efficiency of production.
One particular industry that requires significant control and which presently does not have adequate abilities for this goal is the water distribution networks that bring potable water from water supply sources and water treatment plants providing these water supply sources. It is well recognized that interruption of fluid flow in systems such as water supply systems needs to be minimized to identify and repair any interruption, such as by a pipe rupture or puncture, or by blockage of the line of flow.
Systems have been developed, such as in Kurisu et al U.S. Pat. No. 5,708,195, which relates to pipeline breakage, where individual sensors identify a leak location while being interconnected to neighboring pressure sensors, such that a leak detector sounds an alarm in the control and management center.
In addition to pressure sensors, acoustic sensors have been proposed for water supply systems. Savic U.S. Pat. No. 5,416,724 distinguishes between acoustic signals originating from leaks and signals from ambient acoustic signals. His related patent U.S. Pat. No. 5,623,421 selectively identifies specific spectral lines from generally expected spectra. Sound generated by a leak is propagated through the metal walls of the pipe and through the substance flowing through the pipe. The sound is introduced into a digital processing and pattern recognition device to detect and alert the user of the presence of leaks. Acoustic sensors are placed at a plurality of locations in the system and provide a signal in response to the sounds sensed by the sensor for processing.
With a large number of sensors, it is necessary to evaluate all of the myriad of data to determine what is true and what is false with respect to a possible leak Rogers et al U.S. Pat. No. 5,757,664 uses a computer system to eliminate presumptions as to the accuracy of the measurement apparatus. Primary in this system is the use of data only for precision and calibration accuracy.
One other system has been proposed, by Paulson U.S. Pat. No. 6,082,193, which uses an array of acoustic sensors along a cable deployed in a fluid filled concrete pipeline to monitor reinforcing wire in the concrete. The use of a separate cable of sensors is not practical in many water supply systems because of the branching and divisions of pipe lines to individual locations.
Accordingly, it would be of great advantage in the art if devices could be used to monitor a water distribution network and relay information between the sensing and control elements of the system without the expense of complicated transmission devices.
It would be another great advance in the art if an acoustic communication support could be implemented as an integral part of controllers using appropriate software currently in use.
Other advantages will appear hereinafter.
It has now been discovered that the above and other objects of the present invention may be accomplished in the following manner. Specifically, the present invention provides a system in which the outlet pressure of a pressure reducing valve in a fluid flow system is controlled by a master controller based on direct measurement of pressure at various places in the system to provide the desired pressure at those various places in the system.
The system of this invention includes a plurality of remote pressure sensors, an acoustic transmitter adapted to transmit a signal in relationship to the measured pressure via the medium, such as water, directly to an acoustic receiver. The receiver then provides the measured remote pressure to the master controller that defines the set point for the pressure reducing valve based on the pressure at the remote location, to effectively achieve real time control of the pressure at the remote location.